This likely has already been discovered, but it's possible repeated use Camera Raw processing on a single image.

The technique is to start with a standard raw file in PS ACR, then open it in PS and save as tiff (we know current ACR can open tiff files).

After applying ACR tone changes, then open in PS again and save as tiff again. Then can reopen again in ACR and start over with new tone settings with the last changed image (now in tiff) as a baseline).

Clearly there are limits to have often this can be done w/o introducing artifacts, but I've found it useful.

This likely has already been discovered, but it's possible repeated use Camera Raw processing on a single image.

The technique is to start with a standard raw file in PS ACR, then open it in PS and save as tiff (we know current ACR can open tiff files).

After applying ACR tone changes, then open in PS again and save as tiff again. Then can reopen again in ACR and start over with new tone settings with the last changed image (now in tiff) as a baseline).

Clearly there are limits to have often this can be done w/o introducing artifacts, but I've found it useful.

Any other experience with this 'workflow'?

Thanks

Ron

ACR can be used a filter in PS (w/ recent incarnations)... so why the trouble w/ roundtrips ? and ACR could open .tiffs/.jps for years.

my understanding is that opening tiff files in ACR (both PS and LR) is a relatively recent event.

but that was not my point: repeated opening on a progressively changing image is new for me (i'm used to making the ACR changes to a raw file, then when you reopen that raw file, you see the current state of changes and the sliders are in the changed position - as is).

with this process, the sliders are reset AND with the prior changes just made are in the image. now you can apply further changes (additive if you will) as if starting from new with the revised image.

Use spot-removal to clone a small part of the image over a wide area, many many times, and memory use becomes a problem. Export as TIFF, remove the image from the catalog, close and re-open LR, optimize the catalog, import the TIFF -- and resume cloning, until memory use becomes a problem again, ... (repeat, rinse)

If you want to add more clarity, you can do this in Photoshop with the Unsharp Mask filter. Use a large Radius and a small Amount -- I would suggest starting with Radius = 50 and Amount = 10%. Of course you can change these numbers to get more control over the final look of the filter, so this gives you more control than Lightroom, which just lets you vary the Amount. (IIRC the Radius is set to 100 in LR.)

In this way you can work on a TIFF file that you open from LR into Photoshop, so there is only one raw conversion, plus you end up with more fine control over it.

Yes, certain types of imaging operations can be done iteratively and repeatedly in the manner you describe -- that is, by "round-tripping" the image through Camera Raw multiple times. For example, you can do this with Clarity, sharpening, tone curves, etc.

Note that if you're starting with a raw file, the first trip through Camera Raw / Lightroom will take advantage of the scene-referred (raw) nature of the imaging data. The resulting image data will be a TIFF, PSD, etc. and will be output-referred. Subsequent trips through ACR/Lr will be treating the image as output-referred.

For example, white balance, noise reduction, and highlight recovery are among the controls you should be certain to get right during the first step. If there's highlight information that you didn't recover during the first trip, and then you end up with a TIFF where those highlights are clipped, there's no way to get them back during subsequent trips through ACR/Lr.